Ball race milling cutter and associated cutting plate

ABSTRACT

An indexable cutting plate for ball race milling cutters includes upper and lower parallel surfaces, and an edge surface interconnecting the upper and lower surfaces. Cutting edges are defined by lines of intersection between the edge surface and the upper surface. The cutting edges include a main cutting edge extending radially with reference to an axis of rotation of the cutter, auxiliary cutting edge extending mainly axially, and an angle cutting edge defining a transition between the main and auxiliary cutting edges. The auxiliary cutting edge has a radius of curvature that is larger than that of the angle cutting edge and smaller than twice the diameter of the cutting head on which the cutting plate is mounted.

BACKGROUND OF THE INVENTION

The present invention relates to a cutting plate for a ball race millingcutter and to an appropriate ball race milling cutter per se. Inparticular, such a cutting plate is provided with an upper and a lowersurface that are substantially parallel to one another, whereincircumferential (continuous) edge surfaces connect the upper surface andthe lower surface to one another, and wherein cutting edges areconfigured at least in part along the lines of intersection between theedge surfaces and the upper and/or lower surfaces. The feature that theupper and the lower surface are substantially parallel to one anotherclearly does not exclude deviation from parallel configuration orcontouring with chip-guiding and chip-breaking structures.

The present invention also relates to a corresponding ball race millingcutter that is provided with a shank, a cutting head and a millingcutter axis, wherein at the forward free end of the cutting head thereis provided at least one seat for an appropriate cutting plate.

Lastly, the present invention also relates to a method for manufacturingball races with the aid of ball race milling cutters equipped withcutting plates, wherein active main and auxiliary cutting edges of thecutting plates are engaged respectively.

Corresponding ball race milling cutters and associated cutting plateshave been known for a long time in the prior art, and are used in orderto manufacture so-called ball races by cutting at a camber angle α, thatis to say grooves with a round, but nevertheless generally not exactlycircular cross-section. The groove cross-section is instead configuredsuch that the radius of curvature at the base of the groove is smallerthan the radius of the balls that will roll along this race. The depthof this groove is also generally less than the radius of the balls,wherein in cross-section, the lateral flanks of the groove have a radiusof curvature that is somewhat greater than the radius of the ballsrolling along it, so the balls rolling in the ball race substantiallytouch only the flank areas of the ball race and engage neither with thebase of the groove nor with the upper edges of the groove. This makespossible a very exactly defined position for the balls at the same timeas low rolling resistance, so by means of such ball races, differentmachine parts can be connected that have to move easily against oneanother, even when they are relatively heavy and/or large amounts offorce have to be transmitted between these machine parts (and via theballs lying in between them). Ideally, the cross-section of the ballrace is substantially elliptical with an eccentricity of 1.01 to 1.1,and a large semi-axis symmetrically dividing the ball race, wherein thesmall semi-axis is slightly larger than the radius of the balls thatwill roll in the race, and the eccentricity is matched to the radius ofthe balls such that the points of contact of the balls on the race, seenfrom the cross-section of the balls, lie approximately 70° to 90° apart,that is on the flanks of the ball race at approximately 35° to 45° fromthe base thereof.

FIG. 1 shows by way of an example a cross-section through a so-calledpivot pin in the form of a more or less cylindrical bush on the internalsurface of which there are several ball races axially or slightlyinclined towards the axis, which in cross-section appear approximatelythe shape of a segment of a circle.

FIG. 2 shows in an enlarged detail view that the cross-section of thecorresponding ball race is not circular, but instead elliptical, and issubstantially characterised by a radius of curvature at the base of theball race that is somewhat smaller than the radius of the balls, and bya radius of curvature in the flank area of the groove or respectivelythe ball race, that is larger than the radius of the balls. In the upperarea, the groove width generally exceeds the ball diameter, at least thediameter of the ball at the height of the groove edges.

Corresponding ball races are, as already described, produced in theprior art with special ball race milling cutters that are arranged at aso-called camber angle α to the surface of the work piece, and in theend face area of which at least one specially formed cutting plate islocated with which the desired groove shape is milled. The so-calledcamber angle is the angle between the milling cutter axis and the axisof the ball race or respectively the tangent on the axis in the sectionof the ball race that is currently being worked. Such a camber angle istypically in the range between 10° and 40°.

The cutting plates that are used in the end face area of the millingcutter generally have a shape that is approximately circular, sometimesslightly flattened in plan view, or more or less oval. They cut bothwith a main cutting edge arranged on the end face of the milling cutter,that has a directional component both in the axial direction as well asin a plane perpendicular to the milling cutter axis, and an auxiliarycutting edge that has a directional component more strongly parallel tothe axis of the milling cutter. When using oval or respectivelyapproximately circular cutting plates, the main and auxiliary cuttingedges are obviously rounded and the transition from the main cuttingedge to the auxiliary cutting edges is practically continuous withoutthere being a clear differentiation between main and auxiliary cuttingedges. Generally, however, this prior art can be characterised in thatin the cutting edge section referred to as the “main cutting edge”, theradial component of the cutting edge predominates, whereas the auxiliarycutting edge is defined by a stronger axial component.

The setting of the milling cutter axis in the camber angle, describedhereinabove, with respect to the surface of the work piece isimplemented in that the base of the groove is cut by a part orrespectively a section of the cutting edge of the cutting plate thatlies relatively far forward in the axial direction, and is at a shorterdistance from the axis of the milling cutter than parts of the auxiliarycutting edge set further back axially. This means that the base of thegroove is formed by a cutting edge section rotating on a smaller orbit,and thereby a smaller radius of curvature (if additionally dependent onthe camber angle) than the flank sections of the groove or respectivelythe ball race that are cut by the auxiliary cutting edge areas that arefurther to the rear axially and further away radially from the axis ofthe milling cutter, that, because of the inclined adjustment of themilling cutter with respect to the surface of the work piece, cannothowever reach the base of the groove.

The result is the at least approximately elliptical cross-sectionalshape of the groove shown in principle in FIG. 2.

A disadvantage of the known cutting plates and ball race milling cuttersis nevertheless in that for each ball diameter that necessitates acorrespondingly dimensioned ball race, a cutting plate or respectively acutting plate matched solely to the corresponding ball race has to beused with a milling cutter that has the appropriate diameter. Ascorresponding ball bearings or respectively ball joints are used anddesigned with widely differing diameters of balls, that are typicallybetween 10 and 30 mm, a large number of different cutting plates have tobe stocked in order to be able to correctly mill the proper ball racefor every ball diameter. This means that the cutting plates for eachindividual ball diameter are used in comparatively small numbers, andnevertheless the manufacturer of such ball races must stock a largenumber of such cutting plates in order to be able to produce any desireddimension of ball race. In this way both the individual cutting platesand the manufacturing of such ball races are very expensive.

With respect to this prior art, the object of the present invention isto provide a cutting plate and a corresponding ball race milling cutterthat make it possible to produce ball races for different ball diameterswith one and the same type of cutting plate, also even with differentmilling cutter diameters.

Furthermore, the present invention should make it possible for a ballrace to be created with several cutting edges that are located ondifferent indexable cutting plates.

SUMMARY OF THE INVENTION

With respect to the cutting plate, this object is solved in that thecutting plate is provided with a main cutting edge substantially to bearranged on the end face, and an auxiliary cutting edge, with an anglecutting edge at the transition between the main and auxiliary cuttingedges, which angle cutting edge, in plan view on the upper surface, isrounded with a comparatively small radius for the angle cutting edge,whereby in the same plan view, the auxiliary cutting edge also has aradius of curvature that is clearly larger than the radius of the anglecutting edge, and that is on the other hand smaller than twice themilling cutter diameter for which the cutting plate is provided.

The course of the main cutting edge is therefore not of paramountimportance, in general the main cutting edge is substantially in aradial direction, that is to say mainly in a plane perpendicular to theaxis of the milling cutter. The angle area, or respectively the anglecutting edge has a comparatively small radius and, in contrast to theangle cutting edge, the auxiliary cutting edge has an obvious axialcomponent and is radially further outwards, but for its part is,however, curved, and is at least mainly slightly inclined towards theaxis of the milling cutter. This results in the angle area, namely theangle cutting edge, being clearly offset radially inwards compared tothe parts of the auxiliary cutting edge lying radially furthest out andfurther to the rear axially, and at the same time is arranged in thefrontmost end face area of the milling cutter or respectively of thecutting plate. With appropriate adjustment of the axis of the millingcutter in the camber angle described hereinabove, this means that thebase of the groove is cut by the angle area or respectively the anglecutting edge, while the flanks of the groove or respectively the ballrace flanks, are cut by the auxiliary cutting edge offset further to therear axially and radially further outwards. The curvature thereofensures that the flank sections obtain the desired curvature that inaddition is also dependent upon the milling cutter radius and the camberangle.

Using the indexable cutting plate according to the invention, it ispossible to fit milling cutters in a larger range of diameters, forexample, with a milling cutter diameter between 12 and 18 mm, with oneand the same cutting plate in order to manufacture ball races forcorrespondingly different ball diameters in the same order of size of 12to 18 mm. In order to cover the standard diameter range of 12 to, forexample, 27 mm, only two different cutting plates are thereforenecessary, the radii of curvature of which, on the angle cutting edgesand the auxiliary cutting edges, are matched appropriately.

The manufacturing and stocking costs of the special cutting plates forball race milling cutters can be significantly reduced in this way.Further, the shape of the cutting plate allows the easy attachment of aplurality of cutting inserts onto one tool, preferably of two or threecutting plates at the same or approximately the same angular distancesapart. Intentionally provided small deviations from the same angulardistances produce resonance-free and possibly quieter running of thetool.

Embodiments of the invention are preferred in which the angle areamerges respectively tangentially into the corresponding auxiliarycutting edges and also into the main cutting edges.

An embodiment of the invention is particularly preferred in which thetransition of the angle radius into the auxiliary cutting edge radius isat an angle of transition or respectively a connecting angle τ that issmaller than the camber angle α, wherein the connecting angle τ isdefined by the angle formed by the tangents on the cutting edge in thispoint of transition with the imaginary axis of the milling cutter in thepre-determined state of installation of the cutting plate. In this wayit is ensured that the base of the groove is actually cut by the anglearea with the smaller radius, while the auxiliary cutting edge, that forits part is round, cuts the flank areas.

A connecting angle is preferred in the range between 10° and 25°, whilethe camber angle α can be, for example, in the range of 12° to 45°. Ingeneral, the connecting angle τ is preferably between 2° and 12° lessthan the camber angle, wherein the small differential value ispreferably taken into account with smaller camber angles.

The radius of the angle cutting edge is preferably between 0.2 and 5 mm,and in particular between 0.4 and 2.4 mm. On the other hand, the radiusof the auxiliary cutting edge is clearly larger and in the preferredembodiment of the invention is between 5 and 30 mm, in particularbetween 8 and 25 mm, whereby this radius is nevertheless also dependentupon the diameter of the milling cutter. Advantageously, the radius ofthe auxiliary cutting edge is therefore determined dependent upon themilling cutter diameter for which the cutting plate is provided, and inthis case, the auxiliary cutting edge radius should be between 0.7 timesand 0.95 times the diameter of the milling cutter, which means, theother way around, that for a given cutting plate with a given auxiliarycutting edge radius, the diameter of the milling cutter cancorrespondingly vary in order to satisfy the criterion describedhereinabove, wherein the slight exceeding or falling short of thisrelationship can easily be tolerated.

The cutting plates can have, for example, a rectangular or selectivelyalso a triangular basic shape, as is known in the prior art, wherein theterm “triangular” in this case also includes the so-called trigonalshape, while the term “rectangular” also covers rhombic plates. It issimply of importance that one of the triangular or rectangular sides canfind application as an end face main cutting edge, and can be arrangedsuch that the auxiliary cutting edge connects with the angle cuttingedge at the connecting angle described, and also has the curvaturedescribed hereinabove.

The configuration of the cutting plate as an indexable cutting plate isparticularly preferred, so that once a cutting edge becomes worn,another cutting edge can be put into use. In the case of rectangularindexable cutting plates, such a plate has on its upper side, preferablyin the diagonally opposite corner areas, the transition between the maincutting edge and auxiliary cutting edge, so on the upper side two maincutting edges and two auxiliary cutting edges lie diagonally oppositeone another with an angle cutting edge lying between them.

With such rectangular indexable cutting plates, nevertheless, theunderside of the plate can also be provided with cutting edges,preferably in exactly the same way as on the upper side, but on theremaining diagonal corners.

The ball race milling cutter is characterised by an appropriate plateseat for the plates presently described. Preferably, the ball racemilling cutter according to the invention is provided with a pluralityof seats for appropriate plates, at the same or approximately the sameangular distances apart along its front periphery section.

With respect to the method described in the introduction formanufacturing ball races, the object that forms the basis of theinvention is solved by the use of one or more cutting plates, whereinmain and auxiliary cutting edges are separated by an angle cutting edge,the radius of which is between 0.2 and 5 mm, preferably between 0.4 and2.5 mm, while the radius of curvature of the main and auxiliary cuttingedges respectively is at least five times this, preferably more than tentimes the radius of curvature of the angle cutter.

In the preferred embodiment of the method according to the invention themain cutting edge is substantially straight, which corresponds to a verylarge or respectively infinitely large radius of curvature, and in theradial direction, while the radius of curvature of the auxiliary cuttingedge is in the range between half and twice the milling cutter radius(maximum half-measurement of the ball race). Moreover, using the methodaccording to the invention the cutting plates have all the featuresdefined in the claims.

To the extent that in the description hereinabove and the claims thereare described cutting edges or cutting edge sections curved in a radius,it is clear that these do not absolutely have to have a constant radiusof curvature, but this radius can also vary in the course of therespective sections within the framework of the limits disclosed in theclaims or can also be replaced with a polygon of sections shorter,straighter and angled with respect to one another, when in the centre,beyond the section concerned, average curvatures are produced that fallwithin the ranges claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a section through a prior art pivot pin with a total of six ballraces that are recognizable substantially in cross-section,

FIG. 2 a cross-section through a prior art ball race with a ball runningtherein shown in broken lines,

FIG. 3 a ball milling cutter having a cutting plate according to thepresent invention, and

FIG. 4 an enlarged view of an indexable cutting plate for a ball racemilling cutter according to the according to the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

As has already been described hereinabove with reference to the priorart, ball races are necessary for guiding balls that, for their part,have to provide engagement in at least one direction in an interferencefitting but frictionless manner between different parts that aremoveable to a limited extent with respect to one another. The best knownexamples of this are obviously conventional ball bearings, but thereare, moreover, many other machine elements that have to be connectedtogether such that they are low in friction and moveable to a limitedextent with respect to one another.

FIG. 1 shows a pivot pin 20 in the form of a hollow cylinder, in theinternal surface of which a total of six ball races in the form ofgrooves 6 are milled, that extend substantially axially with a slightinclination, that is not evident here, with respect to the axis of thepin 20.

The cross-section of the ball race that substantially has the shape of around groove 6, as is best seen in the enlargement according to FIG. 2,is not exactly the shape of a segment of a circle, but instead at thebase of the groove 11 has a smaller radius of curvature than on theflanks 12 of the groove, wherein the groove also generally has a greaterwidth in its upper edge area, that is to say is usually not undercut,although in principle, undercut groove flanks 12 would also beconceivable. As is evident in FIG. 2, the ball 13 shown in broken linesrolls in such a groove 6 on the flanks 12 of the groove, and does nottouch the base 11 of the groove. In this way, however, the position ofthe ball 13 in the cross-sectional direction of the groove 6 is moreexactly defined than would be the case if the ball actually rolled onthe base of the groove. With a groove exactly matched to the diameter ofthe ball, with a circular cross-section, even if tolerances wereexceeded to the slightest degree, considerable friction would occur. Bymeans of the two opposite and spaced apart points of contact of the ball13 in the area of the flanks 12 of the groove, greater forces can alsobe transmitted.

FIG. 3 shows a milling tool 10 according to the invention, wherein itdoes not depend upon the more exact configuration of the tool shank butinstead in the first instance upon the fact that it is provided on itsfront cutting head with a plate seat for a cutting plate 1, as is shownin the preferred embodiment in FIG. 4. In FIG. 3 a work piece surfaceand respectively the direction of work of the milling cutter is shown bya horizontal line W, and the axis 7 of the milling cutter is set at anangle α with respect to this horizontal, which angle in this example issomewhat greater than 20°. The main cutting edge 2 of the indexablecutting plate 1 that is shown in the front end face of the millingcutter runs substantially in a radial plane and cuts the largest part ofthe material out of the work piece. The base of the groove orrespectively the inner groove surface is cut by the angle cutting edge 4and the auxiliary cutting edge 3 that can be seen more clearly in FIG.4.

The camber angle α at which the cutting plate 1 normally operates isshown again in FIG. 4. As can be seen, the main cutting edge 2 mergesvia an angle cutting edge 4 with a relatively small radius 41 into theauxiliary cutting edge 3 that for its part has another radius ofcurvature r2 that is nevertheless clearly larger than the radius r1.Furthermore, in FIG. 4 the tangent τ at the transition point between theangle cutting edge 4 and auxiliary cutting edge 3 is indicated and theso-called connecting angle τ that is defined by the angle of thistangent τ to the axis 7 of the milling cutter (in this case to thestraight rear extension of the auxiliary cutting edge 3, that, however,runs parallel to the milling cutter axis 7). It is evident that becauseof this connecting angle τ the base of the groove necessarily has to becut by the part of the angle cutting edge 4 lying in front of thisconnecting area or transition point, whereas flank parts of the groovelying further up from the base are created by the cutting edge sectionsof the auxiliary cutting edge 3 arranged with a larger diameter.

Even when the radius of the milling tools is altered, that is to saymoving the cutting plate 1 radially outwards or inwards relative to theaxis 7 in FIG. 3, the image of FIG. 1 remains fundamentally the same,and the camber angle α can be varied within certain ranges so long as itremains larger than the connecting angle τ. This makes it possible tomanufacture ball races with different diameters or respectively withdifferent dimensions for corresponding different balls with one and thesame type of cutting plate.

Clearly, the milling cutter shown in FIG. 3 preferably has a furthercutting plate in a position offset by 180°, or also in several otherpositions, which are arranged at the same or approximately the sameangular distances apart with respect to the cutting plate 1 shown, andrelative to one another, which is particularly preferred when a highrate of production is sought, and which additionally contributes tosubstantially quieter running of the milling cutter.

What is claimed is:
 1. A cutting plate for machining ball races,comprising upper and lower surfaces oriented substantially parallel toone another and edge surfaces interconnecting the upper and lowersurfaces, a cutting edge structure defined at least in part by anintersection between the edge surfaces and the upper surface; the edgesurfaces including long edge surface, and a short edge surface, the longedge surface extending substantially parallel to a longitudinal axis ofthe insert; the cutting edge structure including a main cutting edge, anauxiliary cutting edge, and an angle cutting edge; each main cuttingedge defined by an intersection of the short edge surface and the uppersurface; the auxiliary cutting edge defined by an intersection of thelong edge surface and the upper surface and oriented at an anglerelative to the main cutting edge; the angle cutting edge connecting themain cutting edge to the auxiliary cutting edge; the angle cutting edge,as viewed in a direction perpendicular to the upper surface, having afirst radius, and the auxiliary cutting edge having a second radiuslarger than the first radius; wherein an angle of transition is formedat a transition point between the angle cutting edge and the auxiliarycutting edge, the angle of transition being formed between thelongitudinal axis and a line tangent to the transition point and beingin the range between 10° and 35°.
 2. The cutting plate according toclaim 1, wherein each of the auxiliary cutting edge and the main cuttingedge join tangentially with respective ends of the rounded angle cuttingedge.
 3. The cutting plate according to claim 1 wherein the first radiusis between 0.2 and 5 mm and the second radius is between 5 and 35 mm. 4.The cutting plate according to claim 1 wherein the first radius isbetween 0.4 and 2.4 mm, and the second radius is between 7 and 25 mm. 5.The cutting plate according to claim 1 wherein the cutting plate isconfigured as an indexable cutting plate with at least two main cuttingedges and two auxiliary cutting edges.
 6. The cutting plate according toclaim 5, wherein the cutting plate is of generally rectangular shape. 7.The cutting plate according to claim 6 wherein the main and auxiliarycutting edges are formed at a corner of the upper surface of the cuttingplate, and corresponding main and auxiliary cutting edges are formed ata diagonally opposite corner of the upper surface, whereby the cuttingplate is indexable.
 8. The cutting plate according to claim 7 whereincorresponding main and auxiliary cutting edges are also formed at eachof two diagonally opposite corners of the lower side, whereby thecutting plate is reversible.
 9. A ball race milling cutter comprising: ashank defining an axis of rotation and including a cutting head; and acutting plate mounted on the cutting head and including upper and lowersurfaces oriented substantially parallel to one another and edgesurfaces interconnecting the upper and lower surfaces; a cutting edgestructure defined at least in part by an intersection between the edgesurfaces and the upper surface; the cutting edge structure including amain cutting edge, an auxiliary cutting edge, and an angle cutting edge;the main cutting edge disposed in a radial plane orientedperpendicularly to the axis of rotation: the auxiliary cutting edgeoriented at an angle relative to the main cutting edge; the anglecutting edge connecting the main cutting edge to the auxiliary cuttingedge; the angle cutting edge, as viewed in a direction perpendicular tothe upper surface, having a first radius, and the auxiliary cutting edgehaving a second radius larger than the first radius: wherein an angle oftransition is formed at a transition point between the angle cuttingedge and the auxiliary cutting edge, the angle of transition beingformed between the axis of rotation and a line tangent to the transitionpoint and being in the range between 10° and 35°.
 10. The ball racemilling cutter according to claim 9 wherein each of the auxiliarycutting edge and the main cutting edge join tangentially with respectiveends of the rounded angle cutting edge.
 11. The ball race milling cutteraccording to claim 9 wherein the first radius is between 0.2 and 5 mmand the second radius is between 5 and 35 mm.
 12. The ball race millingcutter according to claim 9 wherein the first radius is between 0.4 and2.4 mm, and the second radius is between 7 and 25 mm.
 13. The ball racemilling cutter according to claim 9 wherein the cutting head defines adiameter where the cutting plate is mounted, the second radius beingbetween 0.7 and 0.95 times that diameter.
 14. The ball race millingcutter according to claim 9 wherein the cutting plate is configured asan indexable cutting plate with at least two main cutting edges and twoauxiliary cutting edges.
 15. The ball race milling cutter cuttingaccording to claim 9 wherein the cutting plate is of generallyrectangular shape.
 16. The ball race milling cutter according to claim 9wherein the main and auxiliary cutting edges are formed at a corner ofthe upper surface of the cutting plate, and corresponding main andauxiliary cutting edges are formed at a diagonally opposite corner ofthe upper surface, whereby the cutting plate is indexable.
 17. The ballrace milling cutter according to claim 16 wherein corresponding main andauxiliary cutting edges are also formed at each of two diagonallyopposite corners of the lower side, whereby the cutting plate isreversible.
 18. The ball race milling cutter according to claim 9wherein the cutting plate constitutes a first cutting plate, the cutterfurther including at least one additional cutting plate mounted on thecutting head and being identical to the first cutting head.
 19. A methodof manufacturing ball races comprising engaging a surface of a workpiecewith a cutting plate mounted on a rotating shank of a ball race millingcutter; the cutting plate having a cutting edge structure comprising amain cutting edge, an auxiliary cutting edge, and an angle cutting edgeconnecting the main cutting edge to the auxiliary cutting edge; theangle cutting edge having a radius being between 0.2 and 5.0 mm; theradius of each of the main cutting edge and the auxiliary cutting edgebeing at least five times as large as the radius of the angle cuttingedge; wherein the milling cutter is oriented such that the main cuttingedge, the auxiliary cutting edge an angle cutting edge all engage thesurface of the workpiece as the shank rotates.
 20. The method accordingto claim 19 wherein the radius is between 0.4 and 2.5 mm.
 21. The methodaccording to claim 19 wherein the radius of each of the main cuttingedge and the auxiliary cutting edge is more than ten times the radius ofthe angle cutting edge.
 22. The method according to claim 21 wherein themain cutting edge is substantially straight and extends in asubstantially radial direction with reference to an axis of rotation ofthe shank, the radius of the auxiliary cutting edge being in a range ofbetween one-half and twice a radius of a cutting head of the shank. 23.The method according to claim 19 wherein an axis of rotation of themilling cutter forms an angle of camber with the surface of theworkpiece in a range between 12° and 45°.
 24. The method according toclaim 19 wherein the cutting plate comprises upper and lower surfacesoriented substantially parallel to one another and edge surfacesinterconnecting the upper and lower surfaces, a cutting edge structurebeing defined at least in part by an intersection between the edgesurfaces and the upper surface; the cutting edge structure including amain cutting edge, an auxiliary cutting edge, and an angle cutting edge;the main cutting edge disposed in a radial plane orientedperpendicularly to the axis of rotation; the auxiliary cutting edgeoriented at an angle relative to the main cutting edge; the anglecutting edge connecting the main cutting edge to the auxiliary cuttingedge; the angle cutting edge, as viewed in a direction perpendicular tothe upper surface, having a first radius, and the auxiliary cutting edgehaving a second radius larger than the first radius; wherein an angle oftransition is formed at a transition point between the angle cuttingedge and the auxiliary cutting edge, the angle of transition beingformed between the axis of rotation and a line tangent to the transitionpoint and being in the range between 10° and 35°; wherein the millingcutter is rotated about the axis of rotation which forms an angle ofcamber in a range between 12° and 45° with the surface of the workpiece.